Run OCR on all image frames, overlays and overlay frames

[howff]

At the moment IsIdentifiable only looks at the first frame of the image: https://github.com/SMI/IsIdentifiable/blob/169f2da8144086228f20a3f9147bf5ccc792f988/IsIdentifiable/Runners/DicomFileRunner.cs#L236 because frame number is implicitly zero: https://fo-dicom.github.io/html/db4d5ade-f708-0eb5-1e81-39b256fb2822.htm

Images can contain multiple frames: https://dicom.innolitics.com/ciods/us-multi-frame-image/multi-frame/00280008

• IsIdentifiable should run OCR on all frames.

Additionally, images can contain an overlay, "hidden" as the top ("unused") bits in the PixelData: https://dicom.innolitics.com/ciods/us-image/overlay-plane/60xx0102

• IsIdentifiable should run OCR on this old-style overlay plane, too.

Additionally, images can contain up to 16 overlays: https://dicom.innolitics.com/ciods/us-image/overlay-plane/60xx3000 where 60xx could be 6000, 6002, up to 601E.

• IsIdentifiable should run OCR on all overlays.

Additionally, each overlay can consist of multiple frames: https://dicom.innolitics.com/ciods/nm-image/multi-frame-overlay/60xx0015

• IsIdentifiable should run OCR on all frames in each overlay.

[tznind]

DICOM standard allows two specific types of overlays (graphics and ROI) along with the image and overlays are stored as 1-bit image in Overlay Data (60XX, 0050) attribute. A dataset can have up to 16 separate overpay planes (using the repeating groups encoding).

The overlay plane that represents region of interest (ROI) will have value of “R” for Overlay Type (60xx, 0040) attribute and ROI Area (60xx, 1301), ROI Mean (60xx,1302) and ROI Standard Deviation (60xx, 1303) can be used for the corresponding values of ROI. All bits representing ROI will have a value of 1 that represents the pixels under the boundaries of the actual image data.

Graphic Overlay will have value of “G” in Overlay Type (60xx, 0040) attribute and it is used for expressing reference marks (reference line), graphic annotation, or bitmap text etc. Again, all visible values in an overlay plane are set to 1.

The Overlay Rows (60xx, 0010) and Overlay Columns (60xx,0011) specifies the width and height of the overlay plane. Overlay Bits Allocated is always 1 and Overlay Bit Position is 0 (it was used in previous version and usage has been retired). Overlay Origin (60xx, 0050) is used to described the first overlay point with respect to the pixel in the image and 1\1 represents upper left pixel of the image.

https://stackoverflow.com/a/36727987

[rkm]

Another ref we may find useful: https://cdn.ymaws.com/siim.org/resource/resmgr/mimi18/presentations/18cmimi_ml-clunie.pdf

[howff]

This may well already be implemented, but it does require proper tests